For application of various substances to wounds, it is desirable to find a carrier material which is relatively inexpensive, is easily applied to the wound, is a good carrier for medicaments to be applied to the wound, is biodegradable, and is relatively free from any adverse effect on the various aspects of the complex wound healing process. The chitosan gel of the present invention meets these stringent requirements. The chitosan gel may also be obtained and used in the form of a gel-like membrane for the purposes of the present invention.
Chitosan is a relatively inexpensive commercially available material. It is derived from chitin, an insoluble linear polymer of N-acetylglucosamine, found in the hard shells of crustaceans e.g., shrimp, lobster, crab, which are treated to remove extraneous material.
Chitosan is derived from chitin by removal of a proportion of the N-acetyl groups which renders it soluble in many acids, including certain dilute organic acids, such as formic, acetic and propionic acids. Both chitin and chitosan have been used for a variety of purposes, usually as powders, in solution or membranes in the form of viscoses analogous to cellulose viscose. However, these forms are not readily usable for the purpose described above.